<h4>1. 默认值声明options和ngModel绑定的变量，不进行赋值</h4>
<p>设置[(ngModel)]为空数组[]</p>
<ti-treeselect id="treeselect-load" [options]="options" [(ngModel)]="value" placeholder="Please select"> </ti-treeselect>

<div class="current-value-container">
  <pre>Current Select: {{ value | json }}</pre>
</div>

<p>每个组件改变数据，都用下面六个按钮。不变化</p>
<button id="treeselect-change-undefined" tiButton (click)="changeUndefined()">changeUndefined</button>
<span>使用TiTreeUtil.getSelectedData获取选中数据时会报错，需要手动将[(ngModel)]置为空数组</span><br />

<button id="treeselect-change-null" tiButton (click)="changeNull()">changeNull</button>
<span>使用TiTreeUtil.getSelectedData获取选中数据时会报错，需要手动将[(ngModel)]置为空数组</span><br />

<button id="treeselect-change-wrongtype" tiButton (click)="changeWrongType()">changeWrongType</button><br />
<button id="treeselect-change-nulldata" tiButton (click)="changeNullData()">changeNullData</button><br />
<button id="treeselect-change-dataa" tiButton (click)="changeDataA()">changeDataA</button><br />
<button id="treeselect-change-datab" tiButton (click)="changeDataB()">changeDataB</button><br />
